HALACHAH: The Beraisa teaches that one may handle objects that can be fed to animals on Shabbos, such as mustard seeds that are fed to doves, and pieces of glass that are fed to ostriches. Ameimar says that one may handle pieces of glass only if he personally owns ostriches. Rav Ashi says that he may handle glass even though he does not own ostriches, because he is fit to own ostriches. (The Halachic consensus follows the ruling of Ameimar. One must own, or have access to, ostriches in order to be permitted to move glass on Shabbos.)
This Beraisa appears to contradict the Mishnah earlier (126b). First, the Beraisa states that mustard seeds may be handled because they can be used as feed for doves. The Mishnah, though, states that one may not handle mustard seeds. Second, the Beraisa states that items may be handled if they are fit to be fed to animals. The Mishnah, though, states that bundles of straw -- which are fit to be fed to animals -- may be handled only if they were prepared before Shabbos as food for animals.
(a) The RASHBA says that the Beraisa and the Mishnah indeed argue with each other. Both agree with the general principle that one is permitted to handle objects only when the normal usage of that object is a permitted one. Hence, mustard seeds may be handled only if the normal usage of mustard seeds is to feed them to doves. The Beraisa and Mishnah dispute what the normal use of mustard seeds is. According to the Mishnah, the normal use of mustard is for man, and not for birds. The Beraisa maintains that it is also normally used as food for birds. (Alternatively, the Beraisa and Mishnah agree about the frequency at which mustard is fed to birds. They argue whether this degree of frequency is considered a normal use or not.)
Bundles of straw are normally used for burning, and not fodder. Therefore, the Mishnah states that it must be prepared before Shabbos as animal fodder in order to be permitted to be handled on Shabbos. The Beraisa does not argue with this point.
(b) The RIF and RAMBAM, according to the RAN, explain that the Beraisa and Mishnah are not arguing. Rather, the permissibility to use these objects depends on the practice in the place. In a place where it is common to raise doves, mustard seeds may be handled. The Mishnah, though, refers to a place where people do not raise doves, and therefore mustard seeds may not be handled.
HALACHAH: The Rishonim conclude that anything that is commonly fed to an animal that is either commonly owned in this place or owned by the person in question, is permitted to be moved on Shabbos (OC 308:29).
QUESTION: The Gemara cites a Beraisa that states that unsalted fish is Muktzah and may not be handled on Shabbos, and that unsalted meat is not Muktzah and may be handled on Shabbos. RASHI explains that unsalted fish is Muktzah because it is not fit for use today, since people do not throw unsalted fish to dogs. (Presumably, they intend to cook it and eat it themselves after Shabbos.)
Why is unsalted meat different? Unsalted meat should also be Muktzah for the same reason; it will be cooked and eaten after Shabbos rather than fed to dogs!
(a) The BA'AL HA'ME'OR (142b) and TOSFOS (DH Dag) explain that this Beraisa follows the opinion of Rebbi Shimon (Beitzah 27b), who maintains that something that is prepared for human consumption after Shabbos is not Muktzah on Shabbos and may be fed to dogs. Therefore, even though one plans to cook and eat the meat after Shabbos, it is permitted because it is fit for dogs. Fish is Muktzah not because one plans to eat it himself after Shabbos, but because it is not normally fed to dogs. Since unsalted fish is not even fit for dogs, it is Muktzah.
(b) TOSFOS suggest a second answer. One throws neither fish nor meat to dogs, because dogs are able to fend for themselves. Meat, though, is not Muktzah, because it is common to throw meat to a domesticated wild animal (Chayah), which is unable to fend well for itself. Unsalted fish is not thrown even to a wild animal.


QUESTION: The Beraisa says that if a woman in childbirth needs a certain item such as oil, her friend may carry it to her through Reshus ha'Rabim, but she must carry it with a deviation from the normal way of carrying. She should perform the Melachah with a Shinuy, wherever possible, in order to minimize the desecration of Shabbos.
This implies that the laws of Shabbos are not suspended and permitted ("Hutrah") for the sake of Piku'ach Nefesh, but rather they are still in force but merely overridden ("Dechuyah") for the sake of Piku'ach Nefesh. Had they been completely suspended, it would be permitted to do a Melachah for the sake of Piku'ach Nefesh without any Shinuy. Why, then, do the Poskim rule that Shabbos is "Hutrah" for the sake of Piku'ach Nefesh (see BI'UR HALACHAH OC 328 who cites the ROSH and MAHARAM MI'ROTENBURG who ascribe to this view)?
ANSWER: The MISHNAH BERURAH (OC 330:5) explains that a woman in labor is considered to be in a lesser degree of danger than someone who is in mortal danger due to another cause, because birth is a natural and common situation which normally does not result in death, even though it is dangerous. Therefore, when Shabbos must be desecrated for a woman in childbirth, if it is possible to be Mechalel Shabbos with a Shinuy, then one should use a Shinuy. In other cases of Piku'ach Nefesh, however, no effort should be made to do the Melachah with a Shinuy. (See Insights to Nidah 38:5.)